[Edratman]

An additional major factor is what administration values your starting and second castles have. The range for each is substantial, especially considering terrain modifiers for second castles. The data base complied by Edi combined with the manual is the way to go. For example, if you are Caelum, with a starting 30 admin castle, you could plunk down your second castle almost anywhere without driving resources to zero in adjacent provinces. Or if you location allows building of a river fortress or swamp fort, with low admin, you could plop those anywhere also.

The low admin forts are generally cheaper and quicker. You may not be able to get many high resource troops out of it, but it would be a great site for commander building, allowing your capital to be dedicated to building capital only mages and your best troops.

As you can see, I like to build my second fort as soon as possible in a cheap site without regard to choke points or anything else for that matter. The second castle builds alternately commanders and low level mages, as a general rule. I found that I don't like nations that only have one fort build because of this aspect of my playing style.